I like the art style very much! The game itself didn't tell me much about the story behind the game (like why do I have to fight the bossed, and what am I shooting water) but the great visuals made me came up with some interpretation myself.
The fight scenes on the other hand seem not as delicate as the art. It almost feels like I'm playing an interactive comic. The fighting experience could be improved by increasing the pace of the game, adding different types of attack onto each boss, and have the cursor replaced with a crosshair.
Back to the interactive comic topic... this could actually be a great idea! having the camera moving between grids of the comic, and controlling the characters inside them to defeat bosses. If you design several branches on the storyline, all the branches can even be visually seen by the player, so they are encouraged to explore more endings!